> > There are garbage collectors that use mprotect() and SEGV trapping per
> > page. It would be nice if there was a way to change the protections per
> > page without requiring a VMA for each one.
>
> This is actually how Linux used to work a long long time ago - all
> protection information was in the page tables, and you could do per-page
> things without having to worry about piddling details like vma's.
>
> It does work, but it had major downsides. Trivial things like re-creating
> the permission after throwing a page out or swapping it out.
For some uses, spurious SEGV after swap-in might be okay ;-). Garbage
collector might be that example. Pavel
-- Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt, details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/